CMake

CMake is a Cross-Platform buildsystem generator similar to autotools. It generates makefiles to be processed by make.
Get CMake from the official website cmake.org. As of writing version 3.5.2 is the most recent version.

Inkscape development libraries for Windows 64-bit

Get the inkscape-devlibs64 which include pre-compiled binaries of all Inkscape dependencies.

To checkout via Bazaar use the command

bzr checkout --lightweight lp:inkscape-devlibs64 C:\devlibs64

The --lightweight switch ensures that you only have to download the latest version of all binaries, C:\devlibs64 is the folder you want them to be downloaded to.

Building

Environment variables

Edit the file mingwenv.bat in the root directory of the Inkscape source to match you local paths. Most importantly the two lines

IF "%DEVLIBS_PATH%"=="" set DEVLIBS_PATH=c:\devlibs64
IF "%MINGW_PATH%"=="" set MINGW_PATH=C:\mingw64

should point to the folders containing MinGW-w64 and the inkscape-devlibs64.

Whenever you want to build Inkscape open a command prompt (cmd.exe), change into the root directory of the Inkscape source and execute mingwenv.bat to set environment variables.

Compiling build tool

Compile btool (the command line tool that handles the actual build) using

g++ buildtool.cpp -o btool -fopenmp

Compiling Inkscape

Use btool to compile Inkscape compile and create the distribution directory:

btool -file build-x64.xml -j 2

The file build-x64.xml contains the necessary instructions for creating a standard 64-bit build.
If you want to make a GTK+ 3 build use build-x64-gtk3.xml instead (please note that GTK+ 3 builds are experimental and not ready for production yet).

The -j switch allows to instruct btool to use multiple parallel threads to speed up compilation (e.g. 2 in the example above).